/Engine/Plugins/EnhancedInput/Source/EnhancedInput/Public/UserSettings/EnhancedInputUserSettings.h
This does nothing by default, but some subclasses may want to modify the mapping. Perhaps to change to a specific hardware device ID or something like that
virtual void OnKeyMappingUpdated ( [FPlayerKeyMapping](API\Plugins\EnhancedInput\UserSettings\FPlayerKeyMapping) * ChangedMapping, const [FMapPlayerKeyArgs](API\Plugins\EnhancedInput\UserSettings\FMapPlayerKeyArgs) & InArgs, const bool bIsBeingUnmapped )